Basic Thin Film and XRPD Analysis with the Point Detector on the Rigaku Smartlab Multipurpose Diffractometer Scott A Speakman, Ph.D Center for Materials Science and Engineering at MIT For help in the X-ray Lab, contact Charles Settens settens@mit.edu http://prism.mit.edu/xray The Rigaku SmartLab is a multipurpose diffractometer with a wide variety of optics and sample stages that are available. Fast data collection is enabled by a 9 kW rotating anode source which produces a high flux of X-ray intensity. The data collection program for the SmartLab is called SmartLab Guidance. When you select a package from SmartLab Guidance, it will guide you through the process of configuring the instrument, aligning the sample, and collecting data. This mode of operation is slightly slower than a fully manual operation of the instrument, but it means that you are more empowered to collect data from your sample in a variety of configurations. This SOP will walk you through using the Smartlab with the Scintillation Point Detector in either Bragg-Brentano or Parallel Beam mode. This mode of data collection is best suited for thin film analysis, though it can also be used for analysis of powders. I. Configure the Instrument II. Write a Measurement Program III. Run the Measurement Program IV. When You are Done Appendix A. Terms and Conventions pg pg pg pg pg Revised 9 February 2014 Page 1 of 20 Rigaku Smartlab Operation Checklist 1. Engage the Smartlab in Coral 2. Start the program SmartLab Guidance 3. Assess instrument status and safety a. Is the generator on? b. Is the shutter open? 4. If the generator is off, then turn it on. Turn the generator up to full power, 45 kV and 200mA 5. Select a measurement package 6. Align the instrument optics 7. Load and align your sample 8. Run the package measurement 9. When finished a. Determine if someone is using the SmartLab later the same day. i. If someone is using the SmartLab later the same day, then turn the generator power down to its stand-by level, 20 kV and 10 mA ii. If no one is using the SmartLab later the same day, then turn the generator off b. Retrieve your sample c. Clean the sample stage and sample holders d. Copy your data to a secure location e. Disengage the Smartlab in Coral Revised 9 February 2014 Page 2 of 20 Managing the Rotating Anode Generator When the Smartlab is not being used for an extended period, the rotating anode generator should be turned off to conserve the life of the anode and filament. When the rotating anode generator is first turned on, the instrument requires 20 minutes to warmup before it is ready for use. Therefore, use the following guidelines for turning the rotating anode generator on and off: 1. If you are going to be the first person to use the instrument for the day, plan to turn the instrument on 20 minutes before you will start using it. a. If you contact SEF staff (settens@mit.edu) ahead of time, we will try to turn the instrument on first thing in the morning so that the instrument will be ready when you arrive to use it. b. You do not have to engage the Smartlab in Coral while the generator is warming up. You only need to engage the Smartlab in Coral when you start aligning the instrument and getting it ready for your measurement. 2. When you are done using the instrument, look at the schedule in Coral. a. If someone else is using the instrument after you that same day, then just turn the power down to standby mode (20 kV and 10 mA)—do not turn the generator off. b. If nobody else is using the instrument after you that same day, then turn the generator off. 3. Never turn the instrument off from the front panel unless there is an emergency. This would stop the turbopump in addition to turning off the generator. The instrument would then require 1+ hours to turn back on. a. When you turn the generator off from the Smartlab Guidance software, only the X-ray source is turned off. The turbopump continues to run to maintain a good vacuum in the X-ray source. Revised 9 February 2014 Page 3 of 20 I. Configure the Instrument 1. ENGAGE THE SMARTLAB IN CORAL 2. START THE SMARTLAB GUIDANCE SOFTWARE a. If SmartLab Guidance is not running, then start it. Log-in using the account: 4 3 i. Login name: CMSE ii. Leave the Password blank iii. Click OK 3. ASSESS INSTRUMENT STATUS AND SAFETY 1. Main panel Panel used to start and stop SmartLab. 2. Operating panel 3. Door 4. X-ray warning lamp Panel used to turn the internal light on/off. Can be safely opened when shutter is closed. Lights when x-rays are generated. 5. Door-lock button Lock/Unlock the door. 5 2 1 a. Determine if the generator is on. i. The X-ray warning lamp, which is labeled X-rays ON (number 4 in the figure above), will be lit if the generator is on. ii. If the generator is not on, proceed to step 3d on the next page for instructions iii. If the generator is on, then you will need to: 1. evaluate the instrument status, as described below 2. set the generator to maximum power as described on the next page, step 3c b. Determine if a run is in progress. i. The Hardware Control window (pictured right) will tell you if an alignment or measurement is in progress. ii. You can look at the History to see when the scan started and the Measurement Window to see how long the scan was supposed to take in order to judge when the scan will be finished. iii. If a measurement is in progress, either let it finish or stop it 1. To stop a scan, click on the Abort button. 2. Data are not saved automatically when you abort a scan. You should manually save the data that was collected. a. Go to the menu File > Save As… b. If the data is yours, then save it in your folder. c. If the data is somebody else’s, then save it in the folder c:\temp\aborted scans. Name the file with the date and time. iv. If no scan is in progress, proceed to step c, setting the generator to maximum power Revised 9 February 2014 Page 4 of 20 c. Set Generator Power to Maximum i. If the generator was already turned on when you arrived in the lab, then you need to make sure that the generator is at full power ii. Go to the menu Control > XG Control iii. Set the voltage to 45 kV iv. Set the current to 200 mA v. Click the Set button. vi. Click the Close button to close the window vii. Review instructions for opening the instrument doors, then proceed to the next page. d. Turn on the SmartLab Generator (if it is off) i. Click on the Startup button in the left-hand pane of the SmartLab Guidance software. ii. The Startup dialog box will open. In that box: 1. Make sure that the Timer box is NOT checked. 2. Select “Use everyday” in the Generator usage: drop-down 3. Select “Hold” in the XG set: drop-down menu 4. Click the Execute button. iii. A separate Hardware Control window (pictured right) will open which will countdown the time remaining during the Aging process. That window will close when the instrument is ready for use. iv. It will take 18 minutes for the instrument to warm up when it is first turned on. e. To OPEN and CLOSE the Instrument Doors i. Make sure that the shutter is closed 1. If the shutter is open, the red shutter open LED on the Xray tube tower will be lit (shown to the right). 2. If the shutter is closed, you are safe from X-ray exposure even when the generator is on. Proceed to the step ii. 3. If the shutter is open, determine if a measurement is in progress. The Hardware Control window (pictured right) will tell you if an alignment or measurement is in progress. a. If a measurement is in progress, follow the instructions in step b on page 4 to stop the scan and save the data. b. If a measurement is not in progress and the shutter is open, something is wrong. Contact SEF staff for help. ii. Press the Door Lock button on the left door (number 5 in the illustration on page 4) iii. The Door Lock button will light up. Wait until it starts blinking before you try to open the door. The instrument is making sure it is safe before it unlocks the doors. iv. When the Door Lock button begins to flash the door is unlocked. v. GENTLY Slide the doors open. vi. When you are done, GENTLY slide the doors closed vii. Press the Door Lock button to lock the doors again. Revised 9 February 2014 Page 5 of 20 4. SELECT A MEASUREMENT PACKAGE a. In the measurement pane, select either a Preinstalled or a User Defined measurement. i. If you need assistance deciding which measurement is best for your sample, contact SEF staff. ii. Certain measurements ask you to perform hardware changes that require additional training. Do not attempt to change hardware that is unfamiliar to you! If you would like to be trained to use new hardware, contact SEF staff. b. The packages that you can run after completing the Basic Smartlab training are: User-Defined Measurements BB coupled scan PB-PSA coupled scan Phase analysis of thick polycrystalline samples. Phase analysis of polycrystalline samplesespecially those with rough uneven surfaces or when tilting to study preferred orientation Phase analysis of thin polycrystalline films or depth profiling of surfaces. Does not work for samples with preferred orientation. Phase analysis of thin polycrystalline samples. Analysis of thin film thickness and roughness. PB-PSA GIXD Variable Slit-BB XRR PB-medium resolution Preinstalled Measurements Reflectivity (medium resolution PB) Rocking Curve/Reciprocal Space Map (medium resolution PB) Quick Theta/2-Theta Scan (Bragg-Brentano focusing) Precise Theta/2-Theta Scan (Bragg-Brentano focusing) General (Bragg-Brentano focusing) Quick Theta/2-Theta Scan (medium resolution PB/PSA) Precise Theta/2-Theta Scan (medium resolution PB/PSA) General (medium resolution PB/PSA) Reflection SAXS (medium resolution PB) Residual Stress (medium resolution PB/PSA) Don’t use this package- it misaligns the sample. Use the macro instead. Evaluate texture or quality of thin film Phase analysis of polycrystalline samples- works best for thick samples with smooth flat surfaces Phase analysis of polycrystalline samples- works best for thin films or samples with rough uneven surfaces Small angle scattering analysis of thin film Residual stress analysis of non-textured samples The Bragg-Brentano (BB) geometry uses a divergent X-ray beam and parafocusing optics. Incident angle (omega) and diffraction angle (2theta) must be coupled, so that ω=½*2θ. o This provides the best angular resolution for diffraction data If the divergence limiting slit is fixed, then the X-ray beam width decreases during the measurement. For thin films, this will result in a loss of intensity at higher angles. If a variable divergence slit is used, then the divergence aperture will change during the scan in order to maintain a constant X-ray beam width. This will avoid the loss of intensity at high angles from thin films. The Parallel-Beam (PB) geometry uses a Gobel mirror to focus the divergent X-ray beam into a nearly parallel X-ray beam (very low divergence). This allows the incident angle (omega) and the diffraction angle (2theta) to be decoupled. Scans can be executed with a fixed incident angle, allowing for Grazing Incident X-Ray Diffraction (GIXD). o GIXD allows the X-ray beam to be focuses in the surface of the sample, increasing the amount of signal that comes from the thin film or sample surface. o GIXD does not work well for textured thin films. Scans can also be executed with a set angular offset, such that ω=½*2θ+τ. This allows different directions in the sample to be probed. Revised 9 February 2014 Page 6 of 20 c. When you select a measurement, a flow chart will appear with the steps required to execute that measurement. There are always at least three steps: i. Optics Alignment ii. Sample Alignment iii. Measurement d. You have two different ways that you can choose to execute the package: i. This SOP assumes that you will individual execute each step. You will manually proceed from one step to the next. 1. Select each step by clicking on the box in the guidance software. 2. Set the parameters, 3. Click Execute to run the step. 4. Close the dialog when the step is finished. ii. You can also set all parameters and then Run the measurement in a semi-automated fashion. This mode of operation is not covered in this manual. 5. OPTICS ALIGNMENT a. In the Package window, click on the Optics Alignment part. b. Decide whether or not you want to run the full alignment. In the window that opens: i. If you do not want to run the full alignment, then check the box says either “Change optics (quick alignment only)” or “Change optics without alignment”. 1. This will usually collect data with over 90% efficiency. Sometimes you might observe that the quick alignment fails and then you have to run the full alignment. ii. If you want to run the full alignment, do not check this box. 1. The instrument will take 5 to 10 minutes to align all of the optics to provide maximum possible efficiency. You might want to do this if you are performing a difficult or demanding measurement. iii. Click the Execute button. c. The instrument will spend a couple of minutes reading the current instrument configuration and will then produce a guidance window to tell you what physical pieces to change. Revised 9 February 2014 Page 7 of 20 d. The default configuration is the medium resolution parallel beam (PB) or Bragg-Brentano focusing configuration. Assuming that is the configuration that you are starting from, the guidance will look like: e. To change the selection slit i. The Bragg Brentano (BB) selection slit is labeled “BB” on the end. The Parallel Beam (PB) selection slit is labeled “PB” on the end. ii. Pull the slit straight out and then insert the other slit f. To insert the height reference sample plate and the Center_slit i. The height reference sample plate may already be on the sample stage. Otherwise, the wafer sample plate is probably mounted (pictured below) Height reference sample plate wafer sample plate Revised 9 February 2014 Sample spacer Page 8 of 20 ii. If the wafer sample plate is mounted, rotate it CCW to loosen. Then lift the wafer sample plate off of the adapter. iii. If there is a sample spacer mounted, press in on the bar indicated by the arrow below and then turn the spacer CCW to loosen it. Then lift spacer off of the adapter. iv. To put the height reference plate onto the sample stage adapter 1. Line up the screws on the reference plate to the large holes on the adapter, as indicated by the arrows on the figure below 2. Then turn the height reference plate CW to lock it in place. v. Then insert the center slit (pictured below) into the height reference plate. 1. The center slit is labeled on the bottom 2. The center slit will be secured by the clips below the alignment block of the reference plate. 3. The guides on the side of the center slit will make sure that it is properly centered Revised 9 February 2014 Page 9 of 20 g. You may have to change the optics in the ROD adaptor and RPS adaptor, on the detector side of the instrument. i. Parts that fit in the ROD adaptor are labeled with a red + ii. Parts that fit in the RPS adaptor are labeled with a red X iii. To change the optics in the adaptor 1. Use the 2.5mm Allen wrench to loosen the set screw. Do not completely remove the screw. 2. Remove the optic and put it in the glass cabinet. 3. Gently insert the correct optic. a. Some optics can be used multiple ways. The label for the desired mode should be facing towards you. 4. Tighten the set screw so that it is barely snug. Do not overtighten the screw. h. When all components have been changed as instructed by the Guidance software, click OK to close the guidance dialogue window. i. The system will now update the configuration and may align some or all of the optics. During this process, the Hardware Control window will indicate the status of the alignment. j. If preparing for a PB/PSA measurement, part way through the alignment the system might prompt you to change the optic(s) in the ROD and/or RPS adaptors. k. When the alignment is done, the Hardware Control window will close. l. Then click OK on the Optics Alignment window to close it. 6. SAMPLE ALIGNMENT a. You have two options to load your sample in to the instrument i. Load the sample in to a rectangular Rigaku sample holder. 1. Use a glass sample holder for powders. You can select from a well that is 0.2mm deep or 0.5mm deep. 2. Use the aluminum sample holder for solid samples. 3. These are stored in the blue bin on the counter by the sink. Please do not remove sample holders from the lab- they are there for everybody to share!! 4. You will remove the center slit and place the sample holder in the height reference sample plate (pictured on page 9). The sample will not have to be aligned. ii. Put the sample on a wafer sample plate. 1. This is best for coatings on substrates and powder on a ZBH. 2. The sample will be aligned by bisecting the beam. 3. If your sample is less than 20mm x 20mm, you should put a glass slide underneath it, otherwise you may see signal from the sample stage. Revised 9 February 2014 Page 10 of 20 b. In the Package window, select the Sample Alignment part. i. The Sample Alignment window will open. Direction of X-ray beam Sample width Sample thickness c. Select the radio button for the sample alignment technique you want to use. You will usually use the Flat sample option: i. Select Flat sample as long as you are using the wafer sample plate and if your sample is flat and larger than 10mm x 10 mm. Always select it if you are doing a GIXD scan ii. Select “Use the height reference sample plate (no height alignment)” if you are using a Rigaku sample holder loaded into the height reference sample plate. iii. Select “Curved sample (Z scan only)” if you are using the wafer sample plate and your sample has either a curved surface OR if your sample is smaller than 10mm x 10mm at its smallest dimension in the X-ray beam. d. If you select Flat sample or Curved sample, you will be prompted to enter your sample thickness in the Sample thickness (mm) dialog box. If you are setting your sample on a glass slide, include the glass slide thickness in the number. e. There is a difference in the procedure depending on if you are using BB and PB-PSA i. If using BB optics, just select the “Run recommended sequence” radio button. 1. Enter your total Sample Thickness in the appropriate box if using Flat Sample or Curved Sample alignments. ii. If using PB-PSA optics, you must customize the alignment scan. 1. Select the “Customize Conditions radio button 2. Click on the Customize button 3. The Customize window will open 4. Select the Flat sample radio button 5. Enter the approximate thickness of your sample in the Sample thickness (mm) box. 6. Change the IS (mm) value to 0.050 mm 7. Click OK. The Customize window will close. f. Click Execute to run the sample alignment. Revised 9 February 2014 Page 11 of 20 g. The software will instruct you to change the sample stage and to load the sample. i. Follow the instructions on the screen. ii. The software will instruct you to change the sample stage. 1. The software cannot automatically detect the sample stage that is installed, so it will always tell you which one you have to use. 2. If you must change the sample stage, follow the illustrated instructions pages 8-9 3. When selecting the correct Sample Spacer, refer to the numbers in black. Ignore the numbers in red. iii. If using PB-PSA optics, always use the 0.114 PSA. Do not use the 0.5 PSA as the software recommends. You will have to remove both the ROD and RPS optics in order to install the 0.114 PSA (it is a large optic and takes up both spaces). Only tighten the set screw in the ROD adapter (marked with a red +) iv. While you are loading the sample, you should change the IS_L slit if necessary. Because of a flaw in the software, SmartLab Guidance will not properly instruct you to change this slit. You must remember to change it yourself. 1. The IS_L is used to match the X-ray beam length to your sample height. The Rigaku convention for naming these directions is unusual, so see the diagram below. 2. The IS_L slit should be at least 20% smaller than your sample. We usually use the 10mm IS_L and nothing larger. If your sample is smaller than 12mm, however, you should change the IS_L. For example, if your sample has a sample height of 10mm, you should use the 5 mm IS_L. The available IS_L slit sizes are 15, 10, 5, and 2 mm. 3. Change the IS_L (circled in red below) with one of the correct size. Direction of X-ray beam Sample width Sample thickness v. Remove the K-beta filter, if present. This is located in the first slit position on the detector side Revised 9 February 2014 Page 12 of 20 vi. Close the enclosure doors. vii. Click OK in the Guidance dialog. h. While the sample is being aligned, the Hardware Control window will indicate the status of the alignment. i. When alignment is done, the Hardware Control window will close. j. When the alignment is done, look at the scans to make sure that they executed properly i. Look at the Z-scan. The intensity should start at a maximum value, then reduce to zero as the sample begins to block the X-ray beam. The optimal Z position for the sample is when it makes the intensity equal to ½ Imax. ii. Look at the Omega scans (only available if you ran selected Flat Sample for the alignment). 1. The omega scan should have a well-defined maximum iii. If these alignment scans do not look like the executed properly, see Appendix B for suggestions on how to correct the alignment. Counts 4000000 2000000 0 -1.50 Z-scan -1 -0.50 Omega scan Position [°2Theta] (Copper (Cu)) Revised 9 February 2014 Page 13 of 20 7. RUN THE MEASUREMENT a. Click on the General Measurement part in the Guidance flowchart. b. The General Measurement window will open. i. The window will look slightly different depending on if you are running in BraggBrentano (BB) mode or in Parallel-Beam (PB) mode. Bragg-Brentano (BB) dialog box Parallel-beam (PB) dialog box c. Click on the […] button to open the Save As dialog to set the folder and filename for the data to be saved to. Click the Save button once that information is set. d. Click on the Read Current Slits button to load the current optics in to the entries for Soller/PSC (deg), IS L (mm), PSA (deg), and Soller (deg). These optics are listed in the order that they appear in the instrument, going to from the x-ray tube (on the left) to the detector (on the right). For example, the first Soller slit listed is the incident-beam side Soller slit and the second Soller slit listed is the diffracted-beam side Soller slit. e. Change these optics as desired. The recommended settings for PSA and the second Soller slit will be different depending on if you are using BB or PB-PSA optics. i. Soller/PSC (deg) is the incident Soller slit. For BB optics, this should be 5 deg. For PB-PSA optics using the 0.114 deg Sometimes it might be set to 2.5 deg. It PSA (which is usual), this is your only is better to make the diffracted-beam Soller slit. Set it to: side Soller slit smaller rather than this 5 deg for more intensity incident-beam Soller slit smaller if you 2.5 deg for better precision want to reduce peak asymmetry of very 0.5 deg for highly precise quantitative low angle peaks (below 20 deg 2theta) . analysis or to reduce asymmetry of peaks below 15 deg 2theta. If you are using a larger PSA, then follow the recommendations for the BB optics. ii. IS L (mm) is the beam length limiting slit, which is used to match the length of the X-ray beam to the height or your sample. Be sure to refer to the figure on page 12 for direction conventions on the Rigaku. Select a slit (15, 10, 5, or 2 mm) that is slightly narrower than your sample. Revised 9 February 2014 Page 14 of 20 iii. PSA (deg) is the parallel slit analyzer. For BB optics, this should be set Open. For PB-PSA optics, this will normally be set to 0.114 deg. This can be set to 0.5 or 1 deg for more intensity, but the peak resolution will be very poor. iv. Soller (deg) is the diffracted beam Soller slit. For BB optics: For PB-PSA optics: 5 deg for more intensity If using the 0.114 PSA (which is most typical), then set this to None 2.5 deg for better precision If using a larger PSA, then follow the 0.5 deg for highly precise recommendations for the BB optic. quantitative analysis or to reduce This should be 5 deg or 2.5 deg if asymmetry of peaks below 15 deg using 2theta. . f. In the area Monochromization for the BB optics, select K beta filter method unless you are using the diffracted beam monochromator. i. The monochromator is useful to filter out unwanted wavelengths of radiation including fluoresced X-rays. This will greatly improve your signal-to-noise ratio, especially for samples that contain high concentrations of Fe and/or Co. ii. You can only use the monochromator if you have received special training and authorization. See SEF staff if you are interested. iii. If you want to use the monochromator with the PB-PSA optics, a different approach will be required. See SEF staff for help. g. Set your Measurement conditions h. You can check one row to perform one measurement or you can check multiple rows to run several measurements on the same sample. Check each row of measurements you want to execute. i. Multiple scans will be saved to the same file. i. Enter your measurement parameters i. Scan Axis: 1. Select Theta/2Theta for a coupled scan using the conventional Bragg-Brentano geometry where omega must be equal to ½*2Theta. 2. Select 2Theta/Omega for a coupled scan with a tilt offset, such that omega= ½*2theta + offset 3. Select 2Theta for a GIXD measurement ii. Mode is almost always Continuous iii. Range is usually Absolute iv. Enter the Start and Stop values appropriate for the scan range required for your measurement. v. Step is usually 0.02 deg vi. Speed is usually a value from 0.5 to 5 deg/min. Revised 9 February 2014 Page 15 of 20 vii. The next four columns will set the computer controlled optics. These are: 1. IS is the incident slit. a. You can change the units for this slit using the drop-down menu underneath the column label (deg or mm). b. This slit will determine the width of the X-ray beam (see page 12 for Rigaku naming conventions for directions). You do not want the beam to be wider than your sample. 2. RS1 is the anti-scatter slit. a. You can change the units for this slit using the drop-down menu underneath the column label (deg or mm). 3. RS2 is the receiving slit 4. Attenuator is an attenuation foil that will reduce X-ray beam intensity if it might become so intense that it could damage the detector viii. These optics will be set differently for BB coupled scans, PB-PSA coupled scans, and PB-PSA GIXD scans. Note that the units are written differently for different scan conditions! IS RS1 RS2 BB coupled scan 0.25 to 2/3 deg is This should be 0.3mm is normal. normal. Use a the same as the Use smaller for more precise data (with less intensity). Never use smaller slit for lower IS slit. smaller than 0.1mm. angle data or more Use larger (up to 0.6mm) for more precision. intensity at the cost of resolution. Useful for amorphous or nanocrystalline materials where peak width is determined by the sample, not the instrument. PB-PSA coupled scan 0.5 to 2 mm is 10mm 10mm normal. Use a smaller slit for lower angle data. PB-PSA GIXD 0.05 to 0.2 mm is 10mm 10mm scan normal. 𝐼𝑆 If using the parallel-beam (PB) optics, the X-ray beam width can be calculated as sin 𝜔 If using Bragg-Brentano (BB) optics, the X-ray beam width can be calculated using the excel spreadsheet “Rigaku SmartLab Beam Width Calculator.xslx” The depth of penetration of the X-rays into your sample can be calculated using the MAC Calculator in HighScore Plus. See the “HighScore Plus Guide.docx” for instructions. ix. The Attenuator should be set to Open, unless your sample includes a single crystal substrate. Then it should be set to Automatic. This is important to protect the detector. x. If running a BB scan, you must make sure that Voltage is set to 45 kV and Current is set to 200 mA. xi. Click on the Set button in the Options column to open the dialog for angular offsets. Revised 9 February 2014 Page 16 of 20 xii. The Action column for Phi and 2ThetaChi should almost always be set to None. xiii. The other Action columns will be set differently depending on your optics and measurement type. 1. If you are collecting a coupled scan from a sample that does not include a single crystal substrate, using either the BB optics or the PB-PSA optics, then the Action column for both 2Theta and Omega should be set to None. 2. If you are collecting a GIXD measurement using PB-PSA optics, then: a. the Action column for Omega should be set to “Move to origin”. b. The Origin(Center) value will be the omega angle for your GIXD measurement. i. This is usually a value from 0.5 to 2 deg. ii. The shallower the angle, the more the x-ray beam is focused in the surface of the sample. 3. For a 2theta/omega coupled scan, you can set a tilt offset. a. This is useful for avoiding the single crystal peak from a single crystal substrate. This works with either BB or PB-PSA optics. set i. Set the Action column for 2Theta and Omega to “Move to Origin”, ii. enter the starting value of the scan for the 2Theta Origin(Center) iii. enter a value of ½*2Theta+Offset for omega Origin(Center). A typical offset is 1deg. b. This can be used with PB-PSA optics to probe in a different direction rather than normal to the substrate. i. Set the Action column for 2Theta and Omega to “Move to Origin”, ii. enter the starting value of the scan for the 2Theta Origin(Center) iii. enter a value of ½*2Theta+Offset for omega Origin(Center). The offset will dictate the tilt, t, of your analysis. xiv. Click close xv. When ready to collect data, click Execute xvi. A dialog will ask if you want to change the optics from those written in the program. Click NO xvii. Change optics as instructed by the SmartLab Guidance software Revised 9 February 2014 Page 17 of 20 IV. When You are Done 1. When the measurement finishes: a. Your data are automatically saved b. The shutter is automatically closed 2. Look to see if anybody is using the instrument after you. a. If somebody is using the instrument later that day, then turn down the generator power to 20 kV and 10 mA i. Go to the menu Control > XG Control ii. Enter 20 kV for the Voltage and 10 mA for the Current iii. Click the Set button. b. If nobody is using the instrument later that day, then turn the generator off. i. Click the Shutdown button from the packages menu. ii. Click Execute 3. Remove your sample and clean up. 4. Disengage the Smartlab in Coral Appendix A. Terms and Conventions Used Terms Used to Denote an Action In this guide there are several terms that indicate an action. Click Press the left mouse button and quickly release it. Double-click Press the mouse button twice (quickly) on an icon, item, file, etc. Right-click Press the right mouse button and quickly release it. Check/Uncheck Click in a check box () to check it or uncheck it Enter Type in information. This can be either text or numerical data. Press Press a key on the keyboard, or a push-button in a window. Select Move the mouse cursor to the option you want and click the left mouse button. Toggle Switch between parameters or states (for example: On-Off-On). In the examples in this Guide we terminate most actions by saying Press “press ”; you can usually press the Enter key instead. Revised 9 February 2014 Page 18 of 20 Appendix B. Things to try if the Sample Alignment doesn’t work correctly a. When the alignment is done, look at the scans to make sure that they executed properly i. Look at the Z-scan. The intensity should start at a maximum value, then reduce to zero as the sample begins to block the X-ray beam. The optimal Z position for the sample is when it makes the intensity equal to ½ Imax. Imax Counts 4000000 ½ Imax The optimal Z value reduces the X-ray beam intensity to ½ Imax indicating that the sample is bisecting the X-ray beam. 2000000 0 -1.50 Imin=0 1. If Imin does not equal zero, then the X-ray beam is wider than the sample. The automatic alignment performed by the software will be wrong. You will need to manually calculate the optimal Z value. 2. The optimal Z value reduces the X-ray beam intensity to ½ (Imax-Imin) + Imin 3. Drive the Z axis to the optimal value by: a. Select the menu Control > Manual Control b. The Manual Control window will open c. Select Z from the list on the left d. In the upper center of the window is the area “Move conditions” e. Enter the optimal Z value in the “To:” box. Then click the Move button. f. Click Close to close the window. -1 -0.50 Position [°2Theta] (Copper (Cu)) ii. Look at the Omega scans (only available if you ran selected Flat Sample for the alignment). 1. The omega scan should have a well-defined maximum Revised 9 February 2014 Page 19 of 20 a. If the sample does not have a well-defined maximum, re-run the sample alignment using the “Curved sample (Z scan only)” option. 2. The software will mark with an x the position that it identified as the optimal value. Make sure that the marked position is close to what you would select as the center of gravity of the peak. If it does not: a. Use the mouse cursor to determine what you think the optimal omega value is. b. Drive the Z axis to the optimal value by: i. Select the menu Control > Manual Control ii. The Manual Control window will open iii. Select Omega from the list on the left iv. In the upper center of the window is the area “Move conditions” v. Enter the optimal omega value in the “To:” box. Then click the Move button. vi. Click Close to close the window. c. Then re-run the sample alignment using the “Curved sample (Z scan only)” option. Omega scan i. When the alignment is done, click OK to close the Sample Alignment window. Revised 9 February 2014 Page 20 of 20